Locking means for the closure of a container of synthetic plastic material



Aprll 19, 1966 F. MUHLHOFF 3,246,783

LOCKING MEANS FOR THE CLOSURE OF A CONTAINER OF SYNTHETIC PLASTICMATERIAL Filed June 10, 1964 United States Patent O a claims. (l. 21S-42) The present invention relates to containers of synthetic plasticmaterial and more particularly has reference to containers of suchmaterial having a filling opening adapted to be closed by means of acup-shaped closure lid.

In a more specific respect, this invention pertains to a container ofsynthetic material wherein a filling opening located in the top wall ofthe container is closed by a cup-shaped closure or lid having lockingring means lassociated therewith for securing the closure or lid in theclosed position.

Yet more specifically, the invention relates to a container of syntheticplastic material in which a collar on the top wall surrounds the fillingopening and terminates in an inwardly directed ledge which supports aperipheral flange on the cup-shaped closure or lid, a locking ringembraces the collar with the ring having an inwardly directed flange atits upper end tightly engaging the peripheral flange of the closure orlid, and the inner surface of the ring having an annular projection ofsubstantially saw tooth configuration in cross-section adapted to engagean opposed annular projection of similar configuration on the collar inthe locked position of the ring.

An important object of the invention is to provide a container of thecharacter described in which the locking ring cannot be removed byunauthorized persons.

To accomplish the foregoing object, a guard ring of brittle or frangiblesynthetic material is positioned about the lower area of the lockingring and includes an inwardly directed annular projection whichunderlies the lower edge of the locking ring and terminates in closeproximity to the collar on the top wall of the container.

For an authorized person to open the closure, a tool must be insertedbetween the guard ring and the lower edge of the locking ring in orderto pry the locking ring from its locked position. If such an operationis attempted, the guard ring due to its brittle nature, will crack orfracture so that it is readily apparent that an unauthorized person hastampered with the closure. Furthermore, the guard ring also functions asan additional clamping means since su-ch ring prevents any radiallyoutward displacement of the lower area of the locking ring.

Moreover, the opening at the upper end of the locking ring is closed bymeans of a removable disc attached to the inwardly directed flange ofthe locking ring via a line of perforations.

Additional objects and advantages of the present invention will becomemore readily apparent to one skilled in the art from the ensuingdetailed description and accompanying drawings, in which drawings:

FIG. 1 is a vertical sectional view of a container embodying theinvention, and

FIG. 2 is a plan View of the closure shown in FIG. 1.

In the drawing there is illustrated a container C of synthetic plasticmaterial and top wall 12 thereof is provided with a filling opening O.The opening O is adapted to be closed by a cup-shaped lid 5 of suitablematerial such as synthetic plastic material and a locking ring 1 securesthe lid in the closed position.

The filling opening O is defined by an upstanding collar 8 which,adjacent its upper end, is provided with an out- "ice wardly directedannular projection 9 of approximately saw tooth configuration incross-section as shown in FIG. l. The collar terminates in an inwardlyextending ledge 10 which supports peripheral flange 5a of the lid 5.

The lid 5 includes a side wall 5b and a domed lower wall 5c. The lid isreinforced by a plurality of ribs 13 which extend radially of the lowerwall 5c from a cylindrical projection 14 centrally located on the lowerwall (FIG. 2). In additition, the peripheral flange 5a extends inwardlyas shown at 6 and terminates in an annular finger piece 7.

The locking ring 1 is provided with an inwardly directed annularprojection 2 adjacent the lower end and such projection is ofsubstantially saw tooth configuration in cross-section. The upper end ofthe ring terminates in an inwardly extending flange 4 which provides acentral opening 3. When the lid 5 is pressed into the filling openingdue to the inherent elastic deformation characteristic thereof, theperipheral flange 5a tightly engages the ledge 10. The lid 5 is securedin this position by means of the ring 1. More specifically, in thelocked position, the facing shoulders of the annular projections 2 and 9engage (FIG. 1) and the flange 4 is pressed tightly against the outerface of the peripheral flange 5a of the lid. Since the outer surface ofthe respective projections 2 and 9 taper upwardly in the direction ofthe central axis of the container, such projections constitute a slideguide means for the clamping or attachment of the ring 1.

A guard ring 1S of brittle or frangible synthetic material is positionedabout the lower portion of the ring 1. Vertical wall 18a engages the-side wall of the locking ring and a projection 18b extendingperpendicularly from the wall 18a is located between the top wall 12 ofthe container and the lower end of the ring. The projection 18b is ofsuch length as to extend in close proximity of the collar 8.

The guard ring is preferably placed about the ring 1 prior to attachmentto the collar and lid and is pressed upon the collar with the lockingring. During attachment, the elastic wall of the collar 8 can deflectinwardly and thereafter spring back into place after the projections 2and 9 have crossed each other.

The central opening 3 of the ring 1 is closed by means of a tear-outdisc 15 attached to the flange 4 via a line of perforations 16. As shownin FIG. `2, the inner surface -of the disc is also provided with afurther line of perforations 17 which, when depressed, provides a fingeropening.

The invention is not to be confined to any strict conformity to theshowings in the drawings but changes or modifications may be madetherein so long as such changes or modifications mark no materialdeparture from lthe spirit and scope of the appended claims.

What is claimed is:

1. In a container of synthetic plastic material, a container body havinga top wall, means providing a filling opening in said top wall includinga collar projecting from the top wall and terminating in an inwardlyextending horizontal ledge, a cup-shaped closure lid for closing saidfilling opening and having a horizontally disposed peripheral flangetightly pressed against said inwardly extending ledge, a locking ringfor securing said lid in the closed position, said locking ring andcollar each having an opposed complementary annular horizontalprojection engageable when the ring is applied to the collar and lid, aninwardly directed horizontal flange at the upper end of the ring fortightly engaging the peripheral flange of the lid and providing acentral opening, a guard ring of brittle synthetic material having avertical side wall and an annular projection extending perpendicularlyinwardly from the lower end of the side wall, said side wall embracing 3the lower area of the locking ring with said projection being positionedbetween the lower edge of' the locking ring and the top wall of thecontainer and terminating in proximity to said collar and an annulartear-o1 dise attached to the ange of the locking ring along a line ofperforations for closing the central opening.

2. The container as claimedk in claim 1, in which each complementaryannular projection isV of substantially saw tooth congurationin-cross-section. l

3. The container as claimed inclaim 2, in which said lid includesadomed-wall and a plurality of radially extending ribs on the inner faceof said wall for reinforcing thelid.

References Cited by the Examiner UNITED STATES PATENTS 749,422 1/ 1904Chapman 21S-42 886,619 5/1908 Lundquist 21S-45 2,125,788 8/1938 Johnson215-42 2,587,737: 3/ 19.52 Koster 2154-45 EOREIGN PATENTS,

537,964 3/1957 Canada. 73,313` 6/1960 France. 578,975 7/ 1958- Italy.

GEORGE O. RALSFON, Primary. Examiner.

FRANKLIN. T. GARRETT, Examiner.

1. IN A CONTAINER OF SYNTHETIC PLASTIC MATERIAL, A CONTAINER BODY HAVINGA TOP WALL, MEANS PROVIDING A FILLING OPENING IN SAID TOP WALL INCLUDINGA COLLAR PROJECTING FROM THE TOP WALL AND TERMINATING IN AN INWARDLYEXTENDING HORIZONTAL LEDGE, A CUP-SHAPED CLOSURE LID FOR CLOSING SAIDFILLING OPENING AND HAVING A HORIZONTALLY DISPOSED PERIPHERAL FLANGERIGHTLY PRESSED AGAINST SAID INWARDLY EXTENDING LEDGE, A LOCKING RINGFOR SECURING SAID LID IN THE CLOSED POSITION, SAID LOCKING RING ANDCOLLAR EACH HAVING AN OPPOSED COMPLEMENTARY ANNLAR HORIZONTAL PROJECTIONENGAGEABLE WHEN THE RING IS APPLIED TO THE COLLAR AND LID, AN INWARDLYDIRECTED HORIZONTAL FLANGE AT THE UPPER END OF THE RING FOR TIGHTLYENGAGING THE PERIPHERAL FLANGE OF THE LID AND PROVIDING A CENTRALOPENING, A GUARD RING OF BRITTLE SYNTHETIC MATERIAL HAVING A VERTICALSIDE WALL AND AN ANNULAR PROJECTION EXTENDING PERPENDICULARLY INWARDLYFROM THE LOWER END OF THE SIDE WALL, SAID SIDE WALL EMBRACING THE LOWERAREA OF THE LOCKING RING WITH SAID PROJECTION BEING POSITIONED BETWEENTHE LOWER EDGE OF THE LOCKING RING AND THE TOP WALL OF THE CONTAINER ANDTERMINATING IN PROXIMITY TO SAID COLLAR AND AN ANNULAR TEAR-OFF DISCATTACHED TO THE FLANGE OF THE LOCKING RING ALONG A LINE OF PERFORATIONSFOR CLOSING THE CENTRAL OPENING.